Field of the Invention
The present invention relates to an image pickup element having a layered structure, an image pickup apparatus including the image pickup element, and a method and program for controlling the same. More particularly, the present invention relates to an image pickup apparatus that can detect an evaluation value for photometry, distance measurement and the like in accordance with an image signal.
Description of the Related Art
There is a technology for evaluating and displaying an image by using a signal picked up by an image pickup apparatus. An apparatus disclosed in Japanese Patent Application Laid-Open No. 2009-89105 discloses a live-view readout mode and a focus-detection auto-exposure readout mode. The live-view readout mode is to read out an image-pickup signal for live-view display, while the focus-detection auto-exposure readout mode is to read out, from an image pickup element, an image-pickup signal to be used for a signal for focus detection and photometry information for auto-exposure. These readout modes are cyclically repeated in every frame.
However, since an image signal (i.e. charge) is read out from the image pickup element on a pixel basis in Japanese Patent Application Laid-Open No. 2009-89105, not only a longer time is taken for transferring the charge, but also the amount of data transfer is increased, which increases power consumption.
Further, the image signal that is the output of the image pickup element is subjected to image signal processing performed by another apparatus such as a controller. Accordingly, a large transfer data amount causes increase in processing load of the controller.
In addition, Japanese Patent Application Laid-Open No. 2009-89105 discloses a pixel unit including focus signal detection pixels, which unavoidably decreases an area allotted for the pixels for the image-pickup signal. Since those focus signal detection pixels are not used in obtaining the image-pickup signal (image signal), image quality is deteriorated.
Accordingly, an object of the present invention is to provide an image pickup element and an image pickup apparatus that reduce data transfer time and suppress deterioration in image quality, and a method and program for controlling the same.